152 MICHIGAN SURVEY, 1908. 



certain species of birds in parts of the country, it is not at all im- 

 probable that with the destruction of the forests (which were dense and 

 dominant and tended to limit the abundance of many species frequent- 

 ing the open), and the increase of food in cultivated fields, there has 

 been an increase in the total number of birds, even in spite of the 

 great numbers killed by man. 



But to the phase of succession with which we are primarily concerned, 

 almost no attention has been given, in spite of its fundamental rela- 

 tion to crop rotation and the corresponding avian succession attend- 

 ing this. Indeed there seems to be a very decided need of a thorough 

 investigation and discussion of the general principles underlying all 

 these economic problems, that they may be brought into harmony with 

 the advances made in some other phases of ecology. 



References. 

 Adams, Chas. C. 



1905. The Postglacial Dispersal of the North American Biota. Biol. Bull., 9, 



pp. 53-71. 



Beyer, G. E., Allison, A., and Kopman, H. H. 



1906. List of the Birds of Louisiana. Part 1, The Auk, 23, pp. 1-15. 



Bray, W. L. 



1906. Distribution and Adaptation of the Vegetation of Texas. Bull. Univ. of 

 Texas, No. 82. 



Brewster, W. 



1906. The Birds of the Cambridge Region of Massachusetts. Mem. Nuttall 



Ornith. Club, No. IV. 



Brown, R. A. 



1907. A Study of the Birds of the Overflow, East of Ann Arbor, Michigan. 



Eighth Ann. Report Mich. Acad. Sci., pp. 162-174. 



Burns, F. Z. 



1901. A Sectional Bird Census. The Wilson Bull., N. S., 8, pp. 84-103. 

 Clements, F. E. 



1905. Research Methods in Ecology. Lincoln, Nebraska. 

 Coville, F. V. 



1893. Botany of the Death Valley Expedition. Cont. U. S. Nat. Herbarium, IV. 

 Coville, F. v., and MacDougal, D. T. 



1903. Desert Botanical Laboratory of the Carnegie institution. Carnegie In- 

 stitution. 



Cowles, H. C. 



1901. Plant Societies of Chicago and Vicinity. Bull. Geog. Soc. Chicago, No. 1. 

 1901. The Physiographic Ecology of Chicago and Vicinity; a Study of the 



Origin, Development and Classification of Plant Societies. Bot. Gaz., 



31, pp. 73-108, 145-182. 



Dixon, Chas. 



1897. The Migration of Birds. London. 

 Fernald, M. L. 



1907. Soil Preferences of Alpine Plants. Rhodora, 9, pp. 149-193. 

 Forbes, S. A. 



1907. An Ornithological Cross-Section of Illinois in Autumn. Bull. 111. St. 

 Lab. Nat. Hist., 7, pp. 305-335. 



